Valvula license model is based on providing the source code under a set of terms that allows to integrate the software into your system and to be able to apply changes (as long as you give back those changes to the public repository and/or you provide those changes to your customs along with reasonable instructions to apply them).
ASPL is releasing Valvula with no royalty or fee, even for commercial development. However, using Valvula in any form doesn't implies to receive guaranteed support and any other professional services. If your intention is to receive professional guaranteed support please read: professional services
With the intention to provide a brief, though not comprehensive, here is the set of general conditions:
All modifications done to the Valvula code must be returned back either to the Valvula repository or included with your application. You can't make private changes to Valvula without making them available to your customers or end users. In the case you want to do so, you must buy a Valvula Commercial License.
You can modify, copy, redistribute and use Valvula and its associated code with no restriction but without ANY WARRANTY, OF ANY KIND. If you want some levels of warranty you must buy a Valvula Support contract.
You can contact us for licensing and support questions at: <firstname.lastname@example.org> (English or Spanish).